This is BankID

BankID is an electronic identification, i.e. an electronic personal identification document which you use to verify your identity. In contrast to physical identity identification documents such as a driving licence and ID cards, you use BankID on websites which need to confirm that you are who you claim to be during logins and signatures. This may, for example, be for your Internet bank, the Swedish Tax Agency or the Swedish Social Insurance Agency. For your BankID to function, in addition to the electronic identification BankID itself, you also need to have the BankID Security Application installed in your computer.
There are three types of BankID - BankID on file, BankID on card and Mobile BankID. The latter, Mobile BankID is used in mobile phones and tablets and is not managed with the BankID Security Application. Therefore, Mobile BankID is not described in detail in this help text. Contact your bank for further information on Mobile BankID.
Which types of BankID you have access to is primarily determined by your Internet bank and you should always go via your Internet bank when you are Getting started with BankID.